GUJARAT TECHNOLOGICAL UNIVERSITY
ELECTRONICS (10) / ELECTRONICS & COMMUNICATION (11)
/INSTRUMENTATION & CONTROL (17)
ELECTRICAL MACHINES
SUBJECT CODE: 2131005
B.E. 3RD SEMESTER
Type of course: Engineering Science (ELECTRICAL)/(INTERDISCIPLINARY)
Prerequisite: Fundamentals of Electrical Engineering
Rationale: NA
Teaching and Examination Scheme:
Teaching Scheme
L
T
P
3
0
2
Credits
C
4
Examination Marks
Theory Marks
Practical Marks
ESE
PA (M)
PA (V)
PA
(E)
(I)
PA
ALA
ESE
OEP
70
20
10
20
10
20
Total
Marks
150
Contents:
Sr.
No.
1.
2.
Subject Content
Hours
Transformers:
Single Phase Transformer: Working principle, Construction, types, EMF
equation, Transformer on no load and on load, vector diagram, exact and
approximate equivalent circuit, O.C & S.C.test on transformer, regulation of
transformer, losses &efficiency, condition for maximum efficiency, Allday
efficiency, Efficiency curve, Sumpner’s test, Auto transformer, Saving of
conductor material, Parallel operation, Conditions, Parallel with equal and unequal
voltage ratio.
3 Phase transformers: Construction, connections, Scott connection, V-V
Connection, Instrument transformers, Current transformers and potential
transformers.
Induction Machines:
3 Phase induction motor: Construction, types, rotating magnetic field, principle
of operation, slip, frequency of rotor current, rotor emf, rotor current, expression
for torque, conditions for maximum torque, torque slip characteristics, starting
torque in squirrel cage and slip ring motors, effect of change in supply voltage on
torque, slip and speed , relation between full load torque and maximum torque,
Power stages in induction motor, vector diagram and equivalent circuit, circle
diagram, construction and calculation, speed control of 3 phase motor, starting
methods for 3 phase induction motor.
Single phase motor:
8
Module
Weightage
18
10
22
Double revolving field theory, starting methods, no load and block rotor test,
equivalent circuit, types of single phase motor
Synchronous Machine: Alternator,Basic principle, construction, pitch factor,
distribution factor, emf equation, alternator on load, voltage regulation,
synchronous impedance method, mmf method, ZPF method, parallel operation,
synchronization of alternator.
Synchronous motor:
Basic principle, methods of starting, application.
DC Machines:
DC Generator: Construction features, emf equation of dc generator, methods of
excitation, losses condition for maximum efficiency, armature reaction, interpoles
and compensating winding, commutation, methods of improving commutation,
characteristics of separately excited and self excited dc generator.
DC Motor: Working principle, voltage equation, condition for maximum power,
characteristics, operating characteristics of dc motor, torque developed, starting ,3
point and 4 point starter, speed control methods, swinburn’s and break test of dc
shunt motor.
Basic of Power transmission and distribution
Operation of different power plants using block diagram-different terminologies
like load factor, diversity factor, plant utilization factors etc.
Classification of transmission lines, transmission line parameters, ABCD
constants, Voltage regulation, Ferranti effect, efficiency of transmission line.
3-phase 3-wire and 3-phase 4-wire distribution system, feeders, distributors, main
lines, comparison of various distribution systems, load power factor improvement
techniques.
Total
3.
4.
5
10
20
10
20
10
20
48Hrs
100
Reference Books:
1.
2.
3.
4.
Text of Electrical Technology;Vol -2; B. L. Theraja, and A. K. Theraja; S. Chand Publication
Electrical machines BY AshfaqHussain; Dhanpatrai and Co.
Principles of Electrical power systems by J. B. Gupta
Generalised theory of rotating machines By P S Bhimra
Course Outcome:
After learning the course the students should be able to :
- Understand working principle, performance, control and applications of AC, DC Machines and
Transformer.
- Carry out basic experiments on AC, DC machine and Transformer.
- Identify, formulate and solve AC, DC machine and Transformer related problems.
- Understand the working and performance analysis of Transmission and Distribution of power.
List of Experiments:
1. To operate two single phase transformers of different KVA ratings in parallel and plot the variation
of currents shared by each transformer versus load current.
2. To perform Open Circuit and Short circuit Test on a transformer and find its efficient and
regulation.
3. Speed control of DC Shunt Motor using a) Armature control and b) field control methods
4. To obtain Magnetizing Characteristics, Internal & External Characteristic of Self Excited DC Shunt
Generator. Also obtain the critical filed resistance of the machine from magnetizing Characteristics.
5. To conduct direct load test on a D.C. compound generator with a) Shunt field alone b) Cumulative
and differential compounding for short and long shunt connections.
6. To obtain Speed-Torque characteristics of DC Series Motor
7. To obtain Speed-Torque characteristics of DC Shunt Motor.
8. To study different starters of D. C. motor.
9. To study different starters of three phase induction motor
10. To perform No load and Block rotor test on induction motor and plot equivalent circuit
11. To Study the effect of Inserting resistance on rotor of Slip ring induction motor.
12. To draw the V curves for synchronous machine
13. To find the voltage regulation of synchronous machine
14. To study capacitor start and capacitor run induction motor
15. Find Voltage regulation and efficiency of Medium transmission line
16. Find Voltage regulation and efficiency of Long transmission line
17. To study various power factor improvement methods
18. To study the block diagram of various power plants
Design based Problems (DP)/Open Ended Problem:
1. To find the applications of various single phase/ three AC and DC motors
2. Design capacitor bank to improve the load power factor
3. Design electrical power distribution system to achieve priscribed voltage regulation
Major Equipments:
Transformer, Single phase and three phase induction motor, synchronous machine,
List of Open Source Software/learning website:
Web-based tools for design:
- http://www.fairchildsemi.com/support/design-tools/power-supply-webdesigner/
- http://www.ti.com/lsds/ti/analog/webench/overview.page
Circuit Lab:
- https://www.circuitlab.com/editor/
Open source Math Tools:
- http://maxima.sourceforge.net/
- http://www.sagemath.org/
- http://www.scilab.org/
- http://www.gnu.org/software/octave/
Learning website
- http://www.electrical-engineering-portal.com/
- http://nptel.iitm.ac.in/courses.php
ACTIVE LEARNING ASSIGNMENTS: Preparation of power-point slides, which include videos,
animations, pictures, graphics for better understanding theory and practical work – The faculty will
allocate chapters/ parts of chapters to groups of students so that the entire syllabus to be covered. The
power-point slides should be put up on the web-site of the College/ Institute, along with the names of
the students of the group, the name of the faculty, Department and College on the first slide. The best
three works should submit to GTU.